請問HDMI線材的好壞是否間接或直接影響到音質呢?

knift wrote:
如果照這理論,我也很好奇USB延長線在訊號正常的情況下,
會否影響檔案傳輸的結果?
會不會原本5MB的MP3經過傳輸後變成5.1MB?或是4.9MB?
會不會原本純淨的照片傳輸後變成有噪點?
另外,以影音解碼擴大機來說,裡面有沒有buffer?
在buffer夠大的情況下,即不即時差在哪?
如果有BUFFER,可以解決時差的問題,
數位傳輸又有糾錯功能,
那還有什麼環節是可能影響音質、畫質的?



檔案傳輸有許多的協定以作資料糾錯或驗證,網路或是作業系統內部的協定都不同,不過都有相對映的協定!檔案大小就是其中一個基本的驗證參數。不過這邊講的檔案傳輸跟即時的program stream/transport stream類型又不同。

理論上BUFFER夠大,資料重傳次數少,重傳的時間也接的上,是不會有什麼問題滴!
實作上我遇過的在個人電腦上就有紅光及藍光光碟讀取上延遲,BUFFER資料output解碼完來不及持續input,播放出來的就破圖或是爆音或是聲音的pitch有問題,端看解碼端跟播放端如何處理。常見的數位電視也有破圖馬賽克的現象這就已經超出BUFFER能處理的範圍(時間到還是要出貨,管你倉庫有多大,沒貨出客人就會知道)。

你的影音解碼擴大機找一台EMI不合格的機器放在旁邊搭一條便宜的HMDI線玩玩看。
就知道BUFFER跟糾錯在影音播放上是不是天下無敵了!




Balason2001 wrote:
HDMI的線材絕對會...(恕刪)
嘛,1W 的啦吧你能期待有多出色的音效。

這和HDMI線材好壞無關~

耳機的問題,你是插螢幕上的音源輸出孔吧。

因為螢幕的啦吧瓦數不高通常會將音量擴大輸出,結果就是破音加暴音。

解決的方法很簡單,將螢幕音量設定調到1就行了。


其實看瓦數就能大略知道喇吧輸出的音質好壞了,電腦螢幕配HDMI純粹是比較方便使用而已。
真是莫名其妙,
都21世紀了,
居然還有人信數位傳輸會失真,
這比19世紀時,信照相會吸人魂魄還丟人,好嗎.

數位資訊傳輸若會失真,
那我寫的軟體改用高檔sata線讀,是不是跑準一點?
我轉帳用鍍金線去轉,會不多轉出一些錢來?

真是一片好樓
我最近也在疑惑這個問題
因為我朋友一直慫恿我買貴的線
原本的線
沒出現花頻,聲音也正常顯示,無雜訊
想說到底要不要花這個錢
看完這棟樓,只得出一個結論
如果出現花頻和破音,才必須要換線
其餘的不如去換其他地方的音響
es4241 wrote:
真是莫名其妙,都21...(恕刪)


如果是檔案傳輸是不會有差異。如果是直接廣播會受到影響,像天氣或環境干擾。如手機也是數位但是有時收訊不良聲音會很差很怪,訊號遺失多。用手機開行動數據傳個MP3,收的人封包會傳到收到完整。

電腦SATA也不應該會像spdif有差。

SPDIF用過光纖跟同軸線錄過同一段檔案,何不自己試一下即知~~




es4241 wrote:
真是莫名其妙,都21...(恕刪)



參考一下HDMI SPEC:
http://www.hdmi.org/download/HDMI_Spec_1.3_GM1.pdf

From 4.2.5 (physical layer):
For each channel under all operating conditions specified in this section the following conditions shall be met. At TMDS clock frequencies less than or equal to 165MHz, the Sink shall recover data at a TMDS character error rate of 10-9 or better, when presented with any signal compliant to the eye diagram of Figure 4-20. At TMDS clock frequencies above 165MHz, the Sink shall recover data on each channel at a TMDS character error rate of 10-9 or better, when presented with any signal compliant to the eye diagram of Figure 4-20 after application of the Reference Cable Equalizer.

有出錯的機會。

From 5.2.3 ("data" coding, basically everything that isn't video or a control signal -- audio, content protection, gamut metadata, etc.):

During the Data Island, each of the three TMDS channels transmits a series of 10-bit characters encoded from a 4-bit input word, using TMDS Error Reduction Coding (TERC4). TERC4 significantly reduces the error rate on the link by choosing only 10-bit codes with high inherent
error avoidance.
...
All data within a Data Island is contained within 32 clock Packets. Packets consist of a Packet Header, a Packet Body (consisting of four Subpackets), and associated error correction bits. Each Subpacket includes 56 bits of data and is protected by an additional 8 bits of BCH ECC parity bits.
...
To improve the reliability of the data and to improve the detection of bad data, Error Correction Code (ECC) parity is added to each packet. BCH(64,56) and BCH(32,24) are generated by the polynomial G(x) shown in Figure 5-5.

資料傳輸有ECC。

From 5.4.4 (video coding):
During video data, where each 10-bit character represents 8 bits of pixel data, the encoded characters provide an approximate DC balance as well as a reduction in the number of transitions in the data stream. The encode process for the active data period can be viewed in two stages.
The first stage produces a transition-minimized 9-bit code word from the input 8 bits. The second stage produces a 10-bit code word, the finished TMDS character, which will manage the overall DC balance of the transmitted stream of characters.

影像基本沒有做ECC。

From 7.7 (audio):
The behavior of the Sink after detecting an error is implementation-dependent. However, Sinks should be designed to prevent loud spurious noises from being generated due to errors. Sample repetition and interpolation are well known concealment techniques and are recommended.

聲音資料有問題則建議接收設備(sink)自己搞定!


你不信21世紀數位傳輸會失真我是信了!

有圓剛硬碟錄影盒這類的,用不同HDMI線錄同一段,比對檔案是不是就知道⋯⋯

150 元一條,樓主是較計較什麼,買個幾千元一條,再來談你的問題!!!!!!!!!!!><
Life too short makes merry while one can..........

luxor_w wrote:
有圓剛硬碟錄影盒這類的,用不同HDMI線錄同一段,比對檔案是不是就知道⋯⋯


這個主意不錯


我是相關科系出身的
本身玩音響也20幾年了

我本身是覺得數位線"理論上沒差"但實際使用上"有差"
實際上就是有差
用條3千以上的線再說吧
好的線上萬也有
一堆人都只用過大通等級的爛線就在那說沒差
根本就是沒聽過好線
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